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Periodontal Defect Associated with an Unusual Root Anatomy of a Maxillary Lateral Incisor: A Case Report

October 1, 2013
by David Chvartszaid, DDS, MSc (Prostho), MSc (Perio), FRCD(C)


Prior to commencing treatment, a prudent practitioner seeks to establish clarity of diagnosis and expected treatment outcome. Occasionally, the clinical presentation is unclear and a degree of uncertainty presides over both the diagnosis and the degree of expected treatment success. In this case report, the clinical presentation did not yield a definitively diagnosis requiring an explorative surgery to determine the cause of a localized infection and to attempt to address it.

A 22-year-old healthy female was referred to the author with a history of recurrent episodes of minor swelling on the mesio-buccal aspect of tooth 22 over the past three years. There was no history of trauma. Tooth 22 tested vital, probing depths were normal and the tooth was not sensitive to percussion. A small draining fistula was noted on the buccal aspect between 21 and 22 corresponding to the area where the patient reported having recurrent minor swellings (Fig. 1). The tooth appeared to have an extra cusp on its mesio-palatal aspect (Fig. 2). Extra-oral examination revealed a high smile line. There were no other clinical findings of significance.

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A periapical radiograph revealed two notable findings in the coronal of the root — mesial bone loss and an unusual convex root anatomy (Fig. 3). The draining fistula was traced with gutta-percha point to the area of site of the bone loss. A cone-beam CT (cbCT) scan was ordered to help with the diagnosis. Interpretation of the cbCT images suggested two important features — the presence of additional tooth material on the mesio-lingual root surface apical to the extra cusp, the absence of pulp tissue within the extra cusp and within the root material apical to it (Fig. 4).  The additional root material was interpreted to be either an accessory “miniature-root” lying right against the main root trunk or an unusually shaped root trunk with two deep palatal grooves creating the appearance of an accessory “miniature-root.” The cbCT was not able to distinguish between these two possible diagnoses.

A working diagnosis of a periodontal defect secondary to an unusual developmental root anatomy (palatal root grooves or an accessory palatal “miniature-root”) was made. From a diagnostic standpoint, the inability to probe into the defect despite its clear superficial location was found to be perplexing. 

An exploratory surgery was planned to debride the osseous defect and to assess clinically the nature of the unusual mesio-palatal root anatomy. Tentative treatment plan was to smooth out the mesio-palatal root surface to avoid re-infection and to perform a guided tissue regeneration procedure to address the periodontal defect. The patient was informed of the various scenarios including the possibility of future need for endodontic therapy and informed consent was obtained. The patient’s high smile line was carefully considered in the planning of the surgical procedure. A palatal approach to the surgical site was chosen to minimize the impact on the post-surgical levels of the buccal and gingival margins (i.e., to minimize risk of buccal gingival recession). If upon entry the defect were found to be inaccessible from the palatal approach, a contingency for raising a buccal flap was also made.

The patient was anaesthetized in a routine manner.  Interestingly, even after the local anaesthetic took effect the defect on the mesial surface could not be probed into utilizing higher than usual probing force. The lack of probing is important in view of the fact that 50 percent of the palatal grooves extend more than 5mm beyond the CEJ (Kogan, 1986). Palatal full thickness flap, without a discard, was elevated leaving the bulk of interproximal papillae intact. Upon flap elevation, the accessory cusp was observed to have grooves running on its mesial and distal surfaces (Fig. 5). The mesio-palatal accessory cusp was removed with a surgical high speed drill to reveal the interproximal osseous defect. No pulpal exposure was observed. Once the extra cusp was removed, it became apparent that the cusp structure continued apically as an accessory root lying right closely to the main root. The accessory root was very narrow in diameter (roughly 1-2mm) and it was easily removed with the use of an elevator (Fig. 6). The periodontal defect area was debrided and the mesio-lingual tooth surface modified slightly to achieve a smooth surface without an undercut (Fig. 7). The osseous defect area was grafted with a bone replacement graft (allograft) and primary flap closure was achieved. Special attention was focused on careful tension-free closure (Fig. 8). The patient tolerated the procedure well and the post-operative course was unremarkable. No loss of papillary tissue height occurred and no sensitivity was reported by the patient at the post-surgical follow-up appointments. The patient has been seen on a regular basis since the surgery and has had no recurrence of the presenting symptoms. The probing depth around tooth 22 remained within normal limits and inflammation-free. The author will continue to monitor the patient on a regular basis. OH

Acknowledgements:
The author would like to thank Drs. Grace Petrikowski and Peter Birek for valuable input during the preparation of this manuscript.


David Chvartszaid is an Assis­tant Professor at the University of Toronto. He maintains a private practice in Toronto.

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